Simple python question

Main Question or Discussion Point

Basically, I have a function that draws a house. You enter (x, y) coordinates to pick where the house is drawn. However, it only lets me draw one house. Why can't I draw more then one house by calling the draw_house(x, y) function multiple times? Here's the code:

Caveat emptor: I don't know anything about python, so I might be way off in left field here.

The code starts off by the call to begin_graphics(), which opens the graphics canvas. Then there is the call to draw_house(90, 90), which causes the body of the draw_house function to execute, drawing a house whose opposite corners are at (90, 90) and (190, 190).

The last line of code in the draw_house function calls update_when, which, when a key is pressed, closes the graphics canvas (which I infer from the comment), so the call to draw_house(200, 200) fails, probably because the graphics canvas is closed.